1. Field of the Invention
This invention relates to battery enclosures and more particularly relates to battery enclosures to contain emissions from battery cell ruptures.
2. Description of the Related Art
As electronic devices become more compact and sophisticated, an ever increasing number contain batteries. As battery technology has developed, batteries have become more and more compact yielding higher energy densities. To achieve the higher energy densities, various metals and materials are used. Many of the metals and other materials used in batteries are toxic to humans.
Batteries are typically made up of one or more cells. Typically, battery cells are designed to contain the battery electrodes and electrolytes and other materials during normal operation. As battery cells age, they become less efficient and start to degrade. In some cases, as batteries degrade they can overheat. In other cases, batteries are charged or discharged in a way that causes overcharging or overheating. Manufacturing defects may also affect battery performance and cause overheating or degraded operation.
Overcharging, overheating, short circuiting, or other common problems associated with battery use can cause a battery cell to rupture. A rupture of a battery cell can cause venting of hot or noxious gases and other hot metals, materials, or liquids. The rupture may be in the form of an explosion. Fires are also known to result from battery cell ruptures.
Rupturing of battery cells may cause venting into an electronic device of materials that may damage the device. In addition, venting of battery cells due to a rupture may damage furniture, floors, walls or anything with which the battery cell materials come into contact. Rupturing of battery cells can also injure people. Numerous instances have been reported by electronics users of injuries and other property damage, including fire. Rupturing of battery cells has become a major concern in the use of electronics with batteries.
Many batteries with a high energy density create gases during the normal operation of charging and discharging. To deal with the gases created during normal operation, some battery makers have created battery cells that expand to contain the gases and then contract. The battery cells are not designed to contain a more violent venting of battery materials which typically cause the battery cells to rupture. Other designs for battery cells take into account the natural forces of pressure from change in altitude or submersion in water such as a lake or ocean. None of the battery cell designs for pressure variations or gas creation are designed to withstand battery venting such as explosion due to overcharging, overheating, etc.
Some rigid battery enclosures are designed to withstand battery cell rupture and venting while preventing emissions to the exterior of the enclosure. The enclosures include thick walls, heavy materials such as steel, or other precautions to contain the emissions from a battery cell rupture. Such rigid enclosures are typically heavier or more expensive than battery enclosures not designed to withstand and contain battery cell rupture.
From the foregoing discussion, it should be apparent that a need exists for an apparatus, system, and method for battery venting containment. Beneficially, such an apparatus, system, and method would withstand the forces associated with battery cell venting and rupture while containing emissions by expanding. The apparatus, system, and method would allow a battery enclosure to expand in one or more chosen directions that may be safer than expansion in other directions. The apparatus, system, and method may also allow a controlled discharge of gaseous emissions to reduce pressure within a battery enclosure after a battery cell rupture.